This invention relates to ion exchange resins and particularly to ion exchange resins in the form of spheroidal beads having high crush strength and high resistance to osmotic shock.
Polymeric ion exchange resins in the form of spheroidal beads are used in many applications as chelating resins and as anion or cation exchangers. In many of these applications, the resins are subjected to stresses which cause substantial breakage in the beads. Said stresses may be mechanical, i.e., due to crushing or collisions between beads or the beads and their containers, or osmotic, such as when the beads are subjected to sudden or repeated changes in electrolyte concentration. The breakage of the ion exchange beads causes substantial losses in the efficiency of the ion exchange column and large costs in replacing the broken resins.
Gel-type (microporous) resins have especially poor osmotic properties and their use in applications where they are subject to sudden or repeated changes in their environment is greatly limited. As a result, macroporous resins are generally employed when good osmotic properties are essential. However, said macroporous resins have very poor mechanical properties and substantially lower ion exchange capacity than gel-type resins.
In view of the deficiencies of known ion exchange resins, it would be desirable to provide a gel-type ion exchange resin having good osmotic and mechanical properties and high ion exchange capacity.